1. Field
One or more embodiments relate to power transmission, and more particularly, to an apparatus for wireless power transmission.
2. Description of the Related Art
Following the development of mobile devices with various functions in applications such as data processing, multimedia, mobile communications, and so on, there has been found a need for a more convenient method to charge mobile terminals or supply power thereto.
Since mobile devices may use different interfaces to supply power, they may need different power supplies or chargers according to their respective specifications.
In order to overcome such an inconvenience, studies on wireless power transmission technologies allowing the wireless supply of power are currently being made. If wireless power transmission technology is put to practical use, mobile devices may be charged conveniently anywhere at any time and the number of wasted dry cells may be reduced, which will reduce the amount of waste materials and pollution.
As an example of one such wireless power transmission method, studies on wireless high power transmission over short distances using electromagnetic resonance based on evanescent wave coupling are currently being made. However, since this technology uses a near-field, low frequencies have to be used to transmit power over a short distance, which leads to an inevitable increase in the size of a resonator.
Also, in order to transmit power while minimizing the effect to humans, a resonator which exploits a magnetic field and not an electric field is needed. A loop resonator is generally used as such a near magnetic field resonator.
However, due to a need for use of low frequencies in order to efficiently transmit power over a short distance, an increase in the size of the loop resonator is not avoidable. Consequently, there are great difficulties in applying the conventional wireless power transmission technology to mobile devices or home appliances.